The influence of acute dietary nitrate supplementation on endothelial function in early post menopausal women
Open Access
- Author:
- Walker, Tia
- Millennium Scholars Program:
- Biology (BIOL)
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisor:
- David Nathan Proctor, Thesis Supervisor
- Keywords:
- nitrate supplementation
menopause
endothelial dysfunction
post-menopausal women
FMD - Abstract:
- Menopause is a pivotal period in a woman’s life when cardiovascular risk dramatically increases, driven by ovarian aging and the loss of estrogen. Estrogen’s effects on the vasculature are mainly mediated by the production of the vasodilator and vasoprotective molecule, nitric oxide (NO). With the onset and continuation of menopause, women’s arteries undergo accelerated aging, characterized by reductions in the endothelial production of NO and a declining ability of conduit arteries (coronary, brachial, etc) to vasodilate. Estrogen replacement has shown beneficial effects on endothelial function in post-menopausal women, yet there are increased risks of adverse events such as stroke or ovarian cancer. These findings have led to the search for safe and effective, non-estrogen therapies for vascular risk reduction in post-menopausal women. Recent reports in our lab reveal that a single dose of nitrate-rich beetroot juice, boosts the production of NO by safely raising nitrite plasma concentrations in older women. Whether nitrate supplementation can augment NO bioavailability and improve endothelial function in more recently postmenopausal women has not been examined. The purpose of the present study, therefore, is to examine the acute effects of nitrate supplementation on vascular endothelial function in a group of recently post-menopausal women. Healthy women will consume either nitrate-rich or a nitrate-depleted placebo beetroot juice on two study visits, in a randomized cross-over, double-blind study. Before and 90 minutes after juice consumption, participants will have the diameter of their right brachial artery measured at rest and following a 5-minute period of forearm blood flow occlusion. Artery diameter images at baseline and during peak dilation are measured using an ultrasound sensor/transducer. These are expressed as the percent change in artery diameter above baseline, FMD%. After the entire study is completed, test order for all subjects will be unblinded and statistical analysis of the results will be conducted. We hypothesize that acute nitrate supplementation will significantly increase brachial %FMD in early post-menopausal women. Once completed, the results of this study will provide insight into the potential of this natural NO-boosting supplement to improve endothelial function during this period of rapidly declining estrogen production.